A deep frown appeared on Sasuke's face when he saw Naruto's calm and confident smile. This was not how he expected the first exchange to happen at all. He thought he could immediately overwhelm Naruto with his speed and give him a severe wound at the start of the fight.
Sasuke shook his head to get rid of idle thoughts and put his focus on Naruto instead. He flared his chakra and shot towards Naruto, this time, with his Sharingan activated.
Naruto reeled back his fist and punched towards the approaching Sasuke, but Sasuke easily dodged Naruto's first punch, while his eyes already detected the path the second one would take. Sasuke decided to block the attack with his hand while slashing his sword at Naruto. Unfortunately, as soon as Naruto's punch collided with his arm, he realized that he had made a mistake. Instead of standing his ground, he slid backward and only came to a halt after a few meters. Rather than blocking a punch, Sasuke felt like he was just hit by a train.
A cocky smile that mimicked Sasuke's previous expression appeared on Naruto's face.
"Hehe, what's wrong, Sasuke? I'm not even warmed up properly, but you are already struggling."
Anger flashed across Sasuke's face when he heard Naruto's mocking words, and a moment later, his hands blurred into a multitude of hand signs.
"[Fire Style: Grand Fireball Technique]"
"Oh, distraction-no-jutsu, a good choice."
Naruto jumped out of the fireball's path, and as he expected, Sasuke was already forming new hand signs.
"[Fire Style: Fire Dragon Jutsu]"
A huge dragon shot out of Sasuke's mouth and approached Naruto, causing his facial expression to become more severe as he quickly went through a few hand signs as well.
"[Wind Style: Massive Breakthrough]"
Strictly speaking, using wind style against fire style was not a good idea, but that was only the case if the two attacks were at the same power level. The moment the two jutsu collided, the fire dragon was shredded to pieces by the powerful storm Naruto's jutsu created.
"[Chidori]"
While the two jutsu collided, Sasuke appeared next to Naruto, his hand already shining with concentrated lightning chakra. Naturally, Naruto's senses picked up Sasuke's movement, and he was already ready for him.
The moment Sasuke's Chidori was about to reach him, a spinning chakra ball formed on his hand, which he swiftly crashed into Sasuke's attack, resulting in a loud explosion.
"[Rasengan]"
*BOOM*
Initially, Naruto rarely used the Rasengan his father created, but recently he has gotten a liking to it and started using it more frequently. A jutsu that can instantly be formed with one hand was incredibly useful, after all.
Naruto and Sasuke both slid back a little after their attacks collided, and while Naruto still had a casual expression on his face, there was a deep frown on Sasuke's. This fight wasn't going how he wanted it to at all.
Moments later, Sasuke's power spiked, and black markings started covering his whole body. He bent his knees and shot towards Naruto far faster than he previously could and slashed his sword at Naruto.
Although Sasuke was faster than he previously was, Naruto still managed to react in time and crossed two kunai in front of him, blocking Sasuke's attack. However, Sasuke tightened the grip on his sword handle and sent some lightning chakra through his hand into the sword.
While Sasuke was using the Sword of Kusanagi, which is considered to be one of the world's strongest swords, Naruto was using normal kunai, so as soon as Sasuke started injecting lightning chakra into his weapon, it easily cut through Naruo's kunai.
Naruto hastily jumped back to avoid getting cut, but in the end, Sasuke's sword still left a small wound on Naruto's body, causing him to smile wryly.
'That was sloppy of me. Good thing nee-san isn't here.'
[Hehe, how about I tell her?]
'Haa? Do you dare? I still have that Madara x Hashirama jutsu in my repertoire.'
[Ohh? Is that how you want to play it? Very well, let's do it. Let's see who takes more damage: Me, who has to watch it, or you, who actually has to make out with your own transformed clones.]
Naruto's mind came to a standstill when he heard Kurama's words as his face became as white as chalk. He never thought about that aspect of his Forbidden Sexy Jutsu.
'Dangerous, way too dangerous. I will have to seal it away forever.'
[Yeah, I thought so.]
Meanwhile, Sasuke saw Naruto's face pale, and a smug expression appeared on his face.
"I see; it seems like you finally understood your situation. That's right, I am an Uchiha, so it is only natural for you to lose against me."
While Sasuke was rambling on, Naruto woke up from his stupor and gave Sasuke a confused look.
'What is he doing? Why did he start monologing?'
[He is an Uchiha.]
'Ah, right, that was a stupid question.'
Moments later, Naruto's pupils changed color and form, and then the tiny cut Sasuke managed to give him healed instantly.
"Oh well, sorry, but I wasn't paying attention to your words at all, Sasuke, and frankly, I don't care either. Since you already activated your hickey-mode, I guess I should get a little serious as well."
Although Sasuke frowned at the term "hickey-mode" Naruto's changed appearance didn't intimidate him in the slightest. Or rather, he was waiting for Naruto to use Kurama's chakra.
"The Kyuubi's power, huh? So what? In the end, all of that is worthless in front of the Sharingan."
Moments later, Naruto and Sasuke's eyes met, and Naruto could feel someone trying to invade his mind.
'Is he trying to get into my mindscape? Is he crazy?'
[I doubt that he even considered whether you know how to control it or not. He probably wants to get in here to temporarily cut my connection to you, which might be possible if I were still sealed.]
'Hehe, but you aren't, which means Sasuke's attempt is doomed to fail from the start. Additionally, there will be lots of opportunities to mess with him while he blindly stumbles around my mindscape. I will let him in without any resistance.'
[That means...]
'Yes, it's exactly as you think.'
'[Time to mess with an Uchiha.]'
Naruto and Kurama's facial features both distorted in glee when they said the last part simultaneously.
Someone is going to have a bad time.